Efficacy of a nootropic spearmint extract on reactive agility: a randomized, double-blind, placebo-controlled, parallel trial

BACKGROUND: Proprietary spearmint extract (PSE) containing a minimum 14.5% rosmarinic acid and 24% total phenolic content, has evinced positive effects on cognition in individuals aged 50–70 with memory impairment after chronic supplementation. To address the growing interest in connecting mental and physical performance, the present study examined whether the nootropic effects of PSE translate into changes in reactive agility following daily supplementation with PSE. METHODS: Utilizing a randomized, double-blind, placebo-controlled, parallel design, healthy, recreationally-active men and women (n = 142) received 900 mg of PSE or placebo (PLA) daily for 90 days. Reactive agility, our primary outcome, was determined by measuring the number of hits and average reaction time (ART) on a Makoto Arena II, a 360(0) audio-visual device that measures stationary, lateral, and multi-directional active choice reaction performance. Safety was evaluated using complete blood count, comprehensive metabolic panel, and blood lipids. Measurements were evaluated on days 7, 30, and 90 of supplementation. RESULTS: An overall treatment effect (p = 0.019) was evident for increased hits with PSE on the stationary test with footplates, with between group differences at Day 30 (PSE vs. PLA: 28.96 ± 2.08 vs. 28.09 ± 1.92 hits; p = 0.040) and Day 90 (PSE vs. PLA: 28.42 ± 2.54 vs. 27.02 ± 3.55 hits; p = 0.002). On the same task, ART improved (treatment effect, p = 0.036) with PSE at Day 7 (PSE vs. PLA: 0.5896 ± 0.060 vs. 0.6141 ± 0.073 s; p = 0.049) and Day 30 (PSE vs. PLA: 0.5811 ± 0.068 vs. 0.6033 ± 0.055 s; p = 0.049). PSE also significantly increased hits (treatment effect, p = 0.020) at Day 30 (PSE vs. PLA: 19.25 ± 1.84 vs. 18.45 ± 1.48 hits; p = 0.007) and Day 90 (PSE vs. PLA: 19.39 ± 1.90 vs. 18.66 ± 1.64 hits; p = 0.026) for the multi-directional test with footplates. Significant differences were not observed in the remaining Makoto tests. PSE was well tolerated as evidenced by no effects observed in the blood safety panels. CONCLUSIONS: The findings of the current study demonstrate that consumption of 900 mg of PSE improved specific measures of reactive agility in a young, active population. TRIAL REGISTRATION: clinicaltrials.gov, NCT02518165. Registered August 7, 2015 – retrospectively registered. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12970-018-0264-5) contains supplementary material, which is available to authorized users.